Heat exchanger



J. C. SHAW HEAT EXCHANGER May 3, 1949.

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HinnH J J. C. SHAW HEAT EXCHANGER May 3, 1949.

Filed May 4, 1948 Patented May 3, 1949 HEAT EXCHANGE]! Joe 0. Shaw, Racine, Win, asaignor to Young Radiator Company, Racine. Wia, a corporation of Wisconsin Application May 4, 1948, Serial No. 25.039

Claims.

In the intensified development that has taken place in recent years in the design and construction of heat-exchange devices for conditioning the lubricant required for aircraft powerpiants. there has been a demand for constructions as small and as compact as possible consistent with a performance adequate for the power plants wherewith such exchangers are intended to be used. One of the imperatives 01 such performance is as rapid a flushing as possible of the coolant-conditioning core following coolant congealment resulting from an exposure to low temperatures, especially during idleness of the aircraft. This demand for compact, emc'ientlyoperated, heat-exchange equipment has been especially active in connection with aircraft designed ior commerical use. Here load capacity is primary and everything is done to reduce to the greatest practicable minimum the space required for equipment.

Experience has taught that quick flushing of congealed core sections of the heat-exchanger is best attained if jets of the warmer coolant, flowing in the heat-exchange core sections directly adjacent the exchanger inlet, can be diverted into those parts of the core sections nearest the exchanger outlet which, necessarily coming later in the sequence of the normal coolant flow. are most likely to be the last sections to decongeal. However, experience has also taught that the most eflicient operation of the exchanger during normal flight conditions is attained when practically all the coolant is required to flow successively through the several sections oi the exchanger core.

The main objects of this invention, therefore, are to provide an improved construction of heatexchange devices which makes possible the utmost compactness, which provides for jets of warm coolant entering the coolant-conditioning core to quickly reach the remoter sections of the core when the coolant is congealed therein, but which precludes the diversion of jets oi coolant during normal operating conditions of the heat exchanger; to provide a heat-exchange device oi this kind having an improved form of valve mechanism for controlling the admission of jets of warm, flowing coolant to the congealed sections or the device; to provide an improved valve mechanism of this kind so constructed and arranged that the non-consecutive, intercore section flow is determined by the differential in coolant pressures in the respective non-consecutive core sections; to provide an improved valve mechanism or this kind adapted for use with heat-exchange devices or the type wherein the partitions which separate the core into two tiers of consecutive flow sections may be either a single wall or a double wall providing a radially-disposed cooiantfiow chamber between the two tiers oi core sections; and to provide an improved valve mechanism of this kind which is simple in construction and practically unfailing in its automatic operation.

In the drawings,

Fig. 1 is a plan view of a preferred form of improved heat-exchange device constructed in accordance with this invention, and of a type used for regulating the temperature of oil used for aircraft engines, certain interior constructions thereof being shown in dotted outline;

Fig. 2 is a side elevation of the same with sections of the outer housing broken away so as to more clearly illustrate the positioning of the improved valve mechanism afiording communication between certain opposed core sections;

Fig. 3 is a partial end elevation of this improved form of heat-exchange device;

Fig. 4 is an enlarged cross-sectional detail of the improved valve mechanism employed in this heat-exchange device as viewed from the plane of the line l-l of Fig. 2;

Fig. 5 is a vertical sectional elevation of a modified form of heat-exchange device employing the improved valve mechanism in connection with a transverse partition which provides an internal warm-up chamber;

Fig. 6 is a longitudinal sectional elevation of the construction shown in Fig. 5 as viewed from the plane 01' the line 86; the line 5-5 in Fig. 6 indicating the plane of the cross-sectional view shown in Fig. 5; and

Fig. '7 is an enlarged cross-sectional detail of the improved valve mechanism employed in this modified form or heat-exchange device, the section being taken on the line 1-1 of Fig. 6.

A heat-exchange device constructed in accordance with this invention, and designed for use in tempering the oil for aircraft power plants, comprises a shell I wherein are arranged the tubes 9 supported at their ends in bonded relationship with each other and with perimetrical portions of the shell, a partition in, and the baflie plates ii to provide two tiers oi core sections i2 surrounding said tubes. Valve mechanisrns l3 arranged at predetermined points on the partition I! control communication between opposite core sections I! under certain predetermined diflerential pressures of the fluid in the respective core sections.

The shell 8 is a single piece of sheet metal with its lateral edges welded together to form a cylindrical housing. Secured to the shell is a fitting l4 providing an inlet port l5, which communicates with the shell port I5, and outlet ports l6 and II, the latter of which communicates with the shell outlet port IT. The fitting would have attached thereto a suitable valve mechanism (e. g., Patent No. 2,293,960) for controlling the flow of fluid to and through said shell, as indicated by the arrows in Fig. 2.

At a point directly opposite the fitting l4 the shell 8 is provided with a drain normally closed by a cap IB.

If and when the circumstances require, the shell may have reinforcing rings l9 secured around the outer peripheries thereof near the opposite ends, as most clearly shown in Figs. 1, 2, and 3.

The tubes 9 are of a conventional form, being cylindrical throughout the greater part of their length but having their ends expanded and hexagonally formed so that the abutting ends support the cylindrical portions in spaced relationship throughout almost the entire length between said heads. Banks of these tubes 9 are arranged to fill the spaces between the shell 8, the partition l0, and the bailies I, and have their hexagonal heads bonded together and to the bounding perimeters of the shell, partition, and baffle to form, in the two compartments on opposite sides of the partition II), the several core sections l2, within which the coolant may be circulated for heat-exchange exposure to the air flowing through the tubes 9.

The partition H] for the preferred embodiment, as shown in Figs. 1, 2, and 3, is a single sheet of material disposed axially of the shell and extending diametrically across the same and bonded thereto along the lateral edges of the partition Ill. At a point most remote from the fitting l4 the partition Ill is formed with an opening 20 which provides communication between core sections |2 on opposite sides of the partition l below the baille plates H and most remote from the fitting I4.

At points intermediate the fitting M and the opening 20 the partition I0 is provided with apertures 2| (see Figs. 2 and 4) affording communication between core sections |2 on directly opposite sides of the partition ||I. These apertures 2| vary in size and certain oi them are controlled by one of the valve mechanisms |3, as will be explained more fully hereinafter. As most clearly shown in Figs. 2 and 3, there are two of these valve-controlled apertures 2|, one of which is located to permit valve-controlled communication between opposed core sections |2 directly adjacent to the fitting l4, whereas the other valvecontrolled aperture 2| is located in the partition H) to permit such communication between opposed core sections next remote from the fitting l4. Also it will be noted from Fig. 2 that the valve-controlled apertures 2| are located at opposite axial edges of the partition ID.

The partition H! for the modification shown in Figs. and 6 comprises a pair of walls 22 and 23 spaced apart so as to form an internal warm-up chamber 24 between them and extending diametrically across the shell and dividing the interior of the shell into two compartments. The chamber 24 is divided into two sections by means of a transverse baffle or partition 25 arranged approximately intermediate the ends of the chamber 24 and extending from the shell adjacent the fitting M to a point near the opposite side of the shell and preferably below the baflle plates H most remote from the fitting l4. The partition plates 22 and 23, at a point most remote irom the fitting N, are formed with transverse, overlapping fianges 28 which provide the opening 2|) sealed off from the internal warmup chamber 24 and affording communication between opposed core sections I2 most remote from the fitting l4. At a point diametrically opposite the opening 20, the wall 22 is formed with a flanged opening 21 which affords communication between the internal warm-up chamber 24 and one of the core sections |2 directly contiguous to the fitting l4 at the outlet end thereof.

At certain points the walls 22 and 23 are formed with abutting depressions or dimples 2B which serve to determine the spacing and the rigidity of these walls. Certain of the depressions are formed with apertures 2| ailording communication between core sections |2 an opposite sides of the wall plates 22 and 23. From Fig. 6, as well as from Fig. 2, it will be observed that not only are these apertures 2| systematically positioned in the partition ID with respect to the baflie plates II but some of the apertures 2| are controlled by valve mechanisms l3 and others are not.

In the preferred embodiment shown in Fig. 2 there are two of these apertures 2| affording communication between the two opposed core sections |2 most contiguous to the fitting I4; one is valve controlled. In the intermediate opposed core sections there are three apertures 2| arranged medially of the baffle plates II and axially of the core; one is valve controlled. The valvecontrolled aperture 2| in the intermediate core section is at the opposite axial end from the valve-controlled aperture between the first above'mentioned core sections. Between the lowermost opposed core sections there are four of these apertures 2| positioned in that part of the partition I0 more remote from the opening 20. None of the latter is provided with a valve mechanism Hi.

In the modification shown in Fig. 6 there is but one of the apertures 2| arranged in the partition Hi and afiording communication between the opposed core sections most continguous to the inlet Hi. This aperture is located at a point remote from the opening 21 and is valve controlled. In the two intermediate opposed core sections l2 there are two of the apertures 2| arranged medially between each pair of baflles H and located near the opposite axial ends of the partition Ill; one of each latter pair of apertures is valve controlled. The valve-controlled aperture between the intermediate core sections next to the sections most continguous to inlet |5 is located at the opposite axial end of the partition Hi from valve-controlled aperture 2| in the core sections directly continguous to the inlet l5 as well as from the valve-controlled aperture between the opposed core sections next remote.

Furthermore, it will be noted that in either of the modifications the valve-co trolled apertures 2| are larger than the ones 't are not valve controlled.

These two types of apertures are provided to perform independent functions.

The smaller apertures, without valve mechanism I3, being unobstructed afiord a continuous communication between the respective opposite core sections |2. This intercore-section flow of coolant between non-continguous sections helps to maintain the exchanger in free or operating condition during normal requirements. However, such small diverted flow is insufiicient to secure the required quick flushing of a congealed core section obtainable from the larger valve-controlled apertures. However, it is imperative that the flow between non-contiguous core sections be cut oil as soon as the previously-congealed core section is decongealed and at least partially flushed. Thus there will be no appreciable diversion of the coolant from its regular flow through the successive core sections which is needed to effect proper conditioning of the coolant for normal flight conditions. To that end, valve mechanism It, which will be more fully described presently, has been provided for each of the larger apertures 2|.

The bafile plates H are arranged two or more on each side of the partition Ill transversely thereto. The baffles on one side are aligned with those on the other. The baifies are secured along their lateral edges respectively to the inner periphery of the shell 8 and to the partition in by spring clips 29. Each baflle II is formed with one or more openings 30 adjacent one end thereof to provide communication between the core sections IE on opposite sides thereof. As will be noted from Fig. 1 these openings 30 are tapered in shape with the wider outer part of the opening adjacent the shell and the narrower inner part of the opening adjacent the partition "I. This tends to ensure a flow of oil to and through tion for any opposed pair of core sections i2 In adjacent bailles the openings 30 are located at opposite ends so that the flow through the core sections is consecutive in opposite directions substantially parallel to the axis of the tubes 9.

As will appear most clearly from Fig. l, the bafiie plates i l are also provided with small bleed apertures II.I placed in that portion of the baffie plate most remote from openings 30. These apertures permit a seepage of coolant between adjacent core sections in the respective tiers as has been more fully set forth in Patent No. 2,376,198, issued May 15, 1945.

The valve mechanism i3, which controls certain of the partition apertures 2|, is a simple conical valve head 3| the stem 32 of which extends through the aperture and is urged by a spring 33 to seat the tapered valve head 3i against the periphery of the opening 2i.

valve stem 32 and having its outer ends bearing against the partition I 0. In the modification shown in Figs. 5 and 6 the spring 33 is a compression spring interposed between the depression or dimple 28 and a washer 34 riveted on the end of the valve stem 32.

-3l opens the aperture 2| and permits a jet of the coolant to enter directly into the opposed core section i2 in advance of the normal oil flow through the intervening core sections.

Such a pressure diflerential usually occurs when for some reason the coolant on the head side of the partition II) has been congealed or reduced to a greater viscosity than the coolant on the spring side of the partition. When the exchanger is in such a condition and an attempt is made to introduce coolant in a warm viscous condition through the inlet port IS the pressure of the incoming coolant is ineflective on the congealed coolant on the opposite side of the partition i As a consequence the pressure of the pressure of spring 33. The valve head 3i retracts and admits a jet of warm coolant into the congealed coolant thus accelerating its decongealing.

In the preferred form shown in Figs. 1 to 4 inclusive the inlet port l5 and the outlet port I! communicate through suitable openings in the shell 8 directly with the contiguous core sections I 2 on the opposite sides of the partition ill respectively. Thus, the coolant entering the inlet port '5 flows through the most contiguous core section l2 and from there consecutively through the core sections on the same side of the partition Ill, whereupon it passes through the opening 20 to the core section l2 on the opposite side of the partition 10 most remote from the fitting l4 and thence consecutively through the core sections on that side of the partition l0 and out through the port I1.

In the modification shown in Figs. 5 to 7 inclusive, the inlet port I5 and the outlet port l6 communicate through suitable shell openings with the chamber 24 between the partition plates 22 and 23 on opposite sides of the baiiie or partition 25, Whereas theoutlet port I! communicates through suitable openings in the shell (see H in Figs. 5 and 6) with the core section I! most contiguous to the fitting id but directly opposite the core section i2 which communicates with the internal warm-up chamber through the opening 21 in the plate 22.

The operation of this improved heat-exchange device is believed to be so obvious from the foregoing as not to require special description.

Other variations and modifications in the details of structure and arrangement of the parts may be resorted to within the spirit and coverage of the appended claims.

I claim:

1. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding said tubes and providing a fluid flow path between said ports, transversely arranged partitions dividing said core into two tiers of superimposed core sections wherein a pair of opposed core sections communicate respectively with said inlet and outlet ports, the partitions which determine the superimposed core sections of each tier each having an opening formed therein providing communication between core sections on the opposite sides of the partition, the openings in adjacent partitions being located at opposite ends whereby the fluid flow is through said core sections consecutively in opposite directions substantially parallel to the axis of said tubes, the partition of which divides said core into two tiers of core sections having an opening formed therein at a point remote from said shell inlet and outlet ports and providing communication between adjacent core sections in opposite tiers, said latter partition also having an aperture formed therein at a point intermediate said last-mentioned opening and said ports providing communication between core sections on opposite sides of said latter partition, and valve means controlling said aperture and adapted to be actuated by a predetermined differential in a condition of fluid in said opposite core sections.

2. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a scaled fluid core within said shell surrounding said tubes and providing a fluid flow path between said ports, transversely arranged partitions dividing said core into two tiers of superimposed core sections wherein a pair of opposed core sections communicate respectively with said inlet and outlet ports, the partitions which determine the superimposed core sections of each tier each having an opening formed therein providing communications between core sections on the opposite sides of the partition, the openings in adjacent partitions being located at opposite ends whereby the fluid flow is through said core sections consecutively in opposite directions substantially parallel to the axis of said tubes, the partition which divides said core into two tiers of core sections having an opening formed therein at a point remote from said shell inlet and outlet ports and providing communication between adjacent core sections in opposite tiers, said latter partition also having an aperture formed therein at a point intermediate said last-mentioned opening and said ports providing communication between core sections on opposite sides of said latter partition, and spring-actuated valve means controlling said aperture, said spring being constituted to normally close said valve but permit its opening when subjected to a predetermined differential in the condition of fluid in said adjacent core sections,

3. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding said tubes and providing a fluid flow path between said ports, transversely arranged partitions dividing said core into two tiers of superimposed core sections wherein a pair of opposed core sections communicate respectively with said inlet and outlet ports, the partitions which determine the superimposed core sections of each tier each having an opening formed therein p.cviding communication between core sections on the opposite sides of the partition, the openings in adjacent partitions being located at opposite ends whereby the fluid flow is through said core sections consecutively in opposite directions substantially parallel to the axis of said tubes, the partition which divides said core into two tiers oi core sections having an opening formed therein at a point remote from said shell inlet and outlet ports and providing communica tion between adjacent core sections in opposite tiers, said latter partition also having apertures formed therein at points intermediate said lastmentioned opening and said ports providing communication between pairs of core sections on opposite sides of said latter partition, and springactuated valve means controlling apertures aiiording communication between at least two pairs of said opposed core sections and adapted to be i said partition having an opening actuated by a predetermined differential in a condition of fluid in the respective opposite core sections.

4. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding said tubes and providing a fluid flow path between said ports, an axially-disposed partition extending diametrically across said shell and dividing said core into two compartments, formed therein remote from said ports and providing communication between said core compartments, a plurality of transversely-alined baiiles dividing each core compartment into a plurality of superimposed core sections with one pair of opposite core sections communicating respectively with said shell inlet port and said outlet port, said bafiles each having an opening formed therein providing communication between core sections on the opposite sides of the baflie, the opening in adjacent baiiles being located at opposite ends whereby the fluid flow is through superimposed core sections consecutively in opposite directions substantially parallel to the axis of said tubes, said partition also having an aperture formed therein providing communication between core sections on opposite sides of said partition but on the same side of alined bailles, and valve means controlling said aperture and adapted to be actuated by a predetermined differential in a condition of fluid in the respective core sections.

5. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding said tubes and providing a fluid flow path between said ports, an axially-disposed partition extending diametrically across said shell and dividing said core into two compartments, said partition having an opening formed therein remote from said ports and providing communication between said core compartments, two or more battles arranged transversely of said partition on each side thereof and dividing each of said core compartments into superimposed core sections with one pair of opposite core sections communicating respectively with said shell inlet port and said outlet port, said bailles each having an opening formed therein providing communication between core sections on the opposite sides of the baffle, the openings in adjacent baiiles being located at opposite ends whereby the fluid flow is through said superimposed core sections consecutively in opposite directions substantially parallel to the axis of said tubes, said partition having an aperture formed therein providing communication between said opposite core sections communicating respectively with said shell inlet and outlet ports, and valve means controlling said aperture and adapted to be actuated by a predetermined differential in the condition of fluid in the respective core sections.

6. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding said tubes and providing a fluid flow path between said ports, an axially-disposed partition extending diametrically across said shell and dividing said core into two compartments, said partition having an' opening formed therein remote from said ports and providing communication between said core compartments, two or more bailies arranged transversely of said partition on each side thereof and dividing each of said core compartments into superimposed core sections with one pair of opposite core sections communicating respectively with said shell inlet port and said outlet port, said baffles each having an opening formed therein providing communication between core sections on the opposite sides of the battle, the openings in adjacent baflles being located at opposite ends whereby the fluid flow is through said superimposed core sections consecutively in opposite directions substantially parallel to the axis of said tubes. said partition having apertures formed therein providing communication between at least two pairs of core sections on opposite sides of said partition, said apertures being located adjacent the opposite axial ends of said partition, and valve means controlling said apertures and adapted to be actuted by a predetermined difierential in the condition of fluid in the respective core sections.

'7. In a device of the class described, the combination of a supporting shell having inlet and outlet ports. a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a. sealed fluid core Within said shell surrounding said tubes and providing a fluid flow path between said ports, an axially-disposed partition extending diametrically across said shell and dividing said core into two compartments, said partition having an opening formed therein remote from said ports and providing communication between said core compartments, two or more bailles arranged transversely of said partition on each side thereof and dividing each of said core compartments into superimposed core sections with one pair of opposite core sections communicating respectively with said shell inlet port and said outlet port, said bafi'les each having an opening formed therein providing communication between core sections on the opposite sides of the baifle, the openings in adjacent baifies being located at opposite ends whereby the fluid flow is through said superimposed core sections consecutivel in opposite directions substantially parallel to the axis of said tubes, said partition having at least two apertures formed therein providing communication between core sections on opposite sides of said partition, one of said apertures being larger than the other, and valve means controlling the larger of said apertures and adapted to be actuated by a predetermined diflerential in the condition of fluid in the respective core sections.

8. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding said tubes and providing a fluid flow path between said ports, a pair of axially-disposed spaced walls extending diametrically across said shell providing a chamber between said walls which divides said core into two compartments, the opposite axial ends of which chamber on the same peripheral side of said shell communicating respectively with said shell inlet and outlet ports, a diametrically-disposed partition arranged between said walls and extending from said peripheral side of said shell to a point near the opposite side whereby communication between said inlet and outlet ports through said chamber is by way of the space between the end of said partition and said opposite side of said shell, two or more ballles extending transversely of said walls on each side thereof and dividing the core compartments on opposite sides of said dividing chamber into a plurality of superimposed core sections, said bailles each having an opening formed therein providing communication between the core sections on opposite sides of the bafile, the openings in the adjacent baiiies being located at opposite ends whereby the fluid flow is through said core sections consecutively in opposite directions substantially parallel to the axis of said tubes, one of said walls having an opening formed therein providing communication between said dividing chamber at a point adjacent to said outlet port and the adjacent core section, said walls at a point remote from said shell inlet port formed to provide an opening therethrough sealed off from said chamber but affording communication between the adjacent core sections, said Walls being formed at certain points to provide an aperture sealed oil from said chamber but affording communication between core sections on the opposite sides of said chamber, and valve means controlling each of said apertures and adapted to be actuated by a predetermined differential in the condition of fluid in said opposite core sections.

9. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding said tubes and providing a fluid new path between said ports, a pair of axially-disposed spaced walls extending diametrically across said shell providing a chamber between said walls which divides said core into two compartments, the opposite axial ends of which chamber on the same peripheral side of said shell communicating respectively with said shell inlet and outlet ports, a diametrically-disposed partition arranged between said walls and extending from said peripheral side of said shell to a point near the opposite side whereby communication between said inlet and outlet ports through said chamber is by way of the space between the end of said partition and said opposite side of said shell, two or more baflles extending transversely of said walls on each side thereof and dividing the core compartments on opposite sides of said dividing chamber into a plurality oi superimposed core sections, said baffles each having an opening formed therein providing communication between the core sections on opposite sides of the baflle, the openings in the adjacent ballles being located at opposite ends whereby the fluid flow is through said core sections consecutively in opposite directions substantially parallel to the axis of said tubes, one of said walls having an opening formed therein providing communication between said dividing chamber at a point adjacent to said outlet port and the adjacent core section, said walls at a point remote from said shell inlet port formed to provide an opening therethrough sealed oil from said chamber but affording communication between the adjacent core sections, said walls being formed at certain points to provide two or more apertures sealed on from said chamber but each aperture providing communication between a pair of core sections on the opposite sides of said chamber, said apertures being located on opposite sides 01' said chamber partition and on opposite sides or a pair or alined transverse bafiies whereby the communication when permitted between salid opposite core sections is consecutive in the direction of the flow of said fluid throush said core sections, and valve means controlling each of said apertures and adapted to be actuated by a predetermined differential in the condition of fluid in said opposite core sections.

10. In a device of the class described, the combination of a supporting shell having inlet and outlet ports, a plurality of axially-disposed tubes filling the space within said shell and having their ends supported in bonded relationship so as to form a sealed fluid core within said shell surrounding tubes and providing a fluid flow path between said ports, a pair of axially-disposed spaced walls extending diametrically across said shell providing a chamber between said walls which divides said core into two compartments; the opposite axial ends of which chamber on the same peripherahside of said shell communicating respectively with said shell inlet and outlet ports, a diametrically-disposed partition arranged between said walls and extending irom said peripheral side 0! said shell to a point near the opposite side whereby communication between said inlet and outlet ports through said chamber is by way of the space between the end of said partition and said opposite side of said shell, two or more baflies extending transversely of said walls on each side thereof and dividing the core compartments on opposite sides of said dividing chamber into a plurality of superimposed core 12 sections, said baiiles each having an opening formed therein providing communication between the core sections on opposite sides or the baille, the openings in the adjacent baiiles being located at opposite ends whereby the fluid flow is through said core sections consecutively in opposite directions substantially parallel to the axis 0! said tubes, one of said walls having an opening formed therein providing communication between said dividing chamber at a point adjacent to said outlet port and the adjacent core section, said walls at a point remote from said shell inlet port formed to provide an opening therethrough sealed off irom said chamber but aii'ordrlng communication between the adjacent core sections, said walls being formed at certain points to provide at least two apertures sealed of! from said chamber and affording communication between core sections on opposite sides of said walls and between a pair of adjacent bailies, said apertures being located on opposite sides of said chamber partition, one of said apertures being larger than the other, and valve means controlling the larger of said apertures and adapted to be actuated by a predetermined difl'erential in the condition of fluid in said opposite core sections.

JOE C. SHAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,293,960 Young Aug. 25, 1942 2,307,300 Ramsaur Jan. 5, 1943 2,352,704 Garner July 4, 1944 2,395,943 Skelly Mar. 5, 1946 

